Finding the Fourth Proportional to 1,686.72, 2,522.88 and 1,317.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,686.72 : 2,522.88 = 1,317.12 : x
2. Step 2: Convert to fraction form
   1,686.72/2,522.88 = 1,317.12/x
3. Step 3: Cross multiply
   1,686.72x = 2,522.88 × 1,317.12
4. Step 4: Simplify right side
   1,686.72x = 3,322,935.71
5. Step 5: Solve for x
   x = 3,322,935.71/1,686.72
6. Step 6: Final answer
   x = 1,970.06